


An Unconventional Experiment

by vintagelilacs



Category: Sherlock (TV)
Genre: 5k of bickering and porn, And a bit of fluff, Blow Jobs, John has the patience of a saint, M/M
Language: English
Status: Completed
Published: 2018-02-28
Updated: 2018-02-28
Packaged: 2019-03-22 02:58:37
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 5,530
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13754823
Author URL: https://archiveofourown.org/users/vintagelilacs/pseuds/vintagelilacs
Summary: "I want to try pleasuring you orally.”“WHAT!”“Oral sex." Sherlock made a vague gesture. "You know, a blowjob." When John didn't immediately reply, he continued. "Also known as fellatio, a hummer, a nosh, giving head...”“I bloody know what it means!”“Oh. Then what's the problem?”





	An Unconventional Experiment

“I’d like to do an experiment,” Sherlock announced, and any hopes John had of a quiet evening vanished. 

John reluctantly lifted his gaze from his laptop. He'd been staring at a half-written blog entry for the better part of the last hour. “That’s nice,” he offered. 

Sherlock's nostrils flared as he huffed out an impatient breath. “I need you to help me with the experiment.” 

Ah. That was decidedly less nice. John maneuvered his laptop onto the cushion beside him before pouring himself a second cup of tea. “Sherlock for the last time, I'm never letting you poison me again.”

“I wasn't poisoning you! I was putting trace amounts of poison in your tea to inoculate you against it. Really, you should be thanking me.” 

“Sherlock,” he sighed gustily. 

“Oh, fine. But this experiment is different. I want to try pleasuring you orally.”

“WHAT!” John jolted in his seat, spilling tea all over his lap. _Shit!_ The tea had cooled off some, and he certainly wasn't at risk of third-degree burns, but it still stung. 

“Oral sex." Sherlock made a vague gesture. "You know, a blowjob." When John didn't immediately reply, Sherlock continued. "Fellatio, a hummer, a nosh, giving head...”

“I bloody know what it means!”

“Oh. So then what's the problem?” 

“What’s the problem?” he echoed, incredulous. “Are you mad?”

Sherlock's face pinched into the expression reserved for when he thought someone was being particularly stupid. “It’s for science, John.”

John sputtered. “Why don't you ask someone else? Make an internet ad for it, or something?” 

“No, no," Sherlock steepled his fingers against his lips. John's eyes lingered on the curve of the man's mouth for a few stolen seconds. "That wouldn't work at all.” 

"Why not?" 

Sherlock waved his hand dismissively, as if he could dispel any of John's doubts. "I can't tell you that, you'd never understand." 

“A-alright," John relented, mainly because the mere idea of Sherlock engaging in such behaviour with a stranger made his stomach tighten in a rather unpleasant manner. Sherlock could get STDs for one. Or... or the person he shagged could turn out to be a serial killer. It really seemed like an unnecessary risk. "Could you at least explain the experiment to me?”

“I thought my explanation, paltry as it was, was sufficient enough.” 

“Not the blowjob. T-the reason why you want to give one.” 

“You needn't concern yourself with the logistics of the experiment." 

"Right, my bad."

Sherlock's eyes narrowed, as if trying to deduce whether John was being sarcastic or genuine. "Just know that you’d be making a vast contribution towards science. Plus, you'd be a very convenient test subject." The larynx in Sherlock's throat bobbed, the first sign that he was perhaps a tad nervous. "And I know you've thought about it. I've caught you staring at my lips before.”

John crossed his arms over his chest defensively. He forced his expression to remain neutral, his voice to remain nonchalant. Sherlock was a bloodhound when it came to sniffing out lies. "Yeah, well, in your case when people stare at your lips, it's probably just them wishing you'd shut up."

"That's not why you stare," Sherlock countered. His eyes possessed a disarming, penetrating quality, as if capable of peering into John's innermost thoughts.

Shit. The bastard really was too observant. "No," John admitted with palpable reluctance. There was no point denying it. He may as well just tell a bold-faced lie while hooked up to a polygraph for all the good it would do him. 

"Is it fair to conclude that you find me attractive?" 

Fishing for compliments, how very like him. "Sherlock, everyone that lays eyes on you finds you attractive." 

"Not everyone," he countered. 

John couldn't hold back a snort. "Just about. And if your appearance doesn't do it for some, your voice definitely will." 

Sherlock straightened. "You're admitting to finding me attractive?" he paused, but John had no intention of interrupting him. "I'm glad you're coming to terms with your latent homosexuality." 

John spluttered. He was starting to get rather tired of others making pronouncements about his sexuality. "I'm not gay." 

"You all but agreed to let me, a fellow man, give you a blowjob." 

John raised his good shoulder in a halfhearted shrug. A blow job was a blow job, no matter who was giving it. "Yeah, well, if you care to know, I'm bisexual." 

"Bise..." Sherlock trailed off. "Oh, yes, that explains a lot." 

"Explains what, exactly?" 

"You'd always seem so defensive when someone assumed your sexuality. I thought it stemmed from insecurity regarding your predilections, but really you were indignant that the possibility of you being bisexual was never considered." Sherlock hums thoughtfully. "I'd always assumed your interest in women may have been a front. Your attraction towards men has always been apparent, after all." 

"Oh, has it now?" 

"Yes. I've checked your pulse on multiple occasions where we've been in compromising situations. Only so much can be attributed to adrenaline. The rest—copious amounts of sweat, raised eyebrows, flared nostrils, lowered voice, dilated pupils, an increased tendency to lick your lips—were definitive signs of arousal." 

"And you think I was attracted to you?" 

"Obviously." 

"Unbelievable," John shook his head. Sherlock's arrogance knew no bounds. Though, really, he shouldn't have been surprised. "I could've been picturing someone else. An attractive female, for instance." 

"Mm, doubtful." 

"Alright, then an attractive male." 

"Other than me, you mean?" 

"Jesus, Sherlock," John sighed. His patience was already fraying. He forced himself to his feet, even if they felt unsteadier than normal. "I need a drink." 

"You just had tea." 

"A real drink." He padded into the kitchen, sidestepping the mess of case files littering the floor. No sooner had he located a bottle of gin, did Sherlock's hand clamp down around his own, prying the bottle from him. 

"You don't want that." 

"You don't know what I do or do not want!" John exploded, his temper spiking. 

Sherlock's lips pursed. He was probably fighting the impulse to lecture John about his temper, and how he needed to start watching his blood pressure. "I only meant, I spiked it with laxatives. If you still wish to drink it, I won't stop you." 

"Why on earth would you spike it with laxatives?" 

"If you must know, I'm having some rather unsavoury company over later this week."

"Is it Mycroft?" Sherlock didn't answer. It was probably Mycroft. 

"John," Sherlock began almost tentatively. He rocked back and forth on the balls of his feet. "I know you're feeling agitated, but the experiment is time-sensitive, and I really do need to know if you plan on being a participant. If not, we can forget the whole thing." 

John closed his eyes. He could not believe this was happening. He'd fooled around countless times with other men during his time in the military. He hadn't shagged any men since returning to London, though he'd definitely flirted with the odd bloke while he was in-between girlfriends. Normally, he wouldn't even consider turning down a blowjob, but this was Sherlock bloody Holmes, and things were never simple when it came to him. A blowjob from him would be nice, and the memory of it would be good fuel for future wanks, but John wasn't sure he'd be able to tolerate a once-off. Generally the appeal in one-night stands stemmed from the anonymity of the experience, the fact that there were no emotions involved. There were a great deal of emotions John felt towards Sherlock. Annoyance and exasperation were certainly near the top of the list, but there was also admiration and loyalty and... yeah, okay. John fancied his flatmate. He could admit it. He fancied the great genius detective. Which is why he shouldn't accept the offer of a blowjob. He was bound to get his heart broken, and it would be his own fault. 

John opened his mouth to enumerate why, precisely, it was such a bad idea, but what came out instead was, "yeah, sure." 

Sherlock positively beamed. "Excellent. I knew you'd agree." 

_Watson, you're a bloody masochist,_ he chided himself. "Um, how do you want to do this?" 

Sherlock frowned. "Are there multiple ways to perform oral sex?" 

"No, no, I meant, do you want to do it here?" 

"Would a bedroom be more preferable?" 

"D-doesn't matter." 

"Alright." And just like that, Sherlock dropped to his knees. Oh, John could get used to this. It was nice being able to look down on him for once. 

Sherlock's tongue swiped across his lips. John tracked the movement hungrily. He’d always been painfully aware of Sherlock’s lips. Always that sweet pink, with that perfect cupid’s bow. John knew what those lips look like when they were dry and cracked, and what they look like after they'd been moistened from Sherlock's tongue.

Yeah, it was probably safe to say that his admiration of Sherlock’s features wasn't as innocent as he’d like to think. 

John flinched when Sherlock's hands came to rest on his thighs. Sherlock arched a brow in question, but didn't remove his hands. Instead, he kneaded at John's thighs until the tense muscles went lax. 

John relaxed. "Do you, uh, want me to take my clothes off?" 

Sherlock's piercing gaze alighted on John's face. "I'll take care of it."

Right, okay. He'll just continue to stand awkwardly. His hands clenched and unclenched at his sides. 

"No need to be so tense, John," Sherlock admonished. "I don't bite." 

"That's reassuring." 

Sherlock deftly popped open the button of his jeans, before getting to work on his zipper. Oh, god. It was happening. It was actually happening. The mere thought of Sherlock's perfect lips wrapped around him made his cock twitch in his pants. He'd indulged in way too many fantasies regarding him. If he managed not to come instantly, it would be an impressive feat. 

"Wait!" John yelped abruptly. Sherlock froze at his interruption. "Condom," he reminded him. If they didn't get one now he didn't know if he'd have the resolve to later. 

"Don't need one." Sherlock tugged John's zipper the rest of the way down. 

"Ah, no." John positioned Sherlock's gorgeous, long-fingered hands away from the vicinity of his crotch. "Arguing with a doctor over safe-sex practices is a waste of your time and mine."

"It will skew the results of the entire experiment!"

"Then you'll just have to take that into account when you do your write-up, or whatever you intend to use the results for."

"John, you're being unreasonable. I've seen your medical records."

"You what? When?"

"The point is, I'm clean and so are you." Sherlock seemed to think that was the end of the discussion. 

"Hang on," John protested, angling his hips away. "How do _I_ know you're clean?"

Sherlock huffed. "Because I just told you." 

"And if you tell me that you've thrown away your secret stash of cigarettes, am I supposed to believe that too?" 

Sherlock's lips twisted into a discontented moue. 

"Using a condom won't make the experience any less... well. It won't have much of an effect on it." 

"But I want to ta—" Sherlock cut himself off, his cheeks flushing a deep crimson. _Interesting._ It wasn't often that the cool and aloof detective was afflicted with embarrassment. John wasn't entirely sure what brought the blush to the man's face. If offering to give his flatmate a blowjob hadn't made Sherlock embarrassed, what caused him to be now? 

"Right," John shook his head. "It's settled, then. I'll even get the condoms. Is cherry-flavoured alright?" 

"Cherry? _That's_ the best flavour you could find?" Sherlock's nose crinkled in disgust. 

"They were on sale, you git." 

"Hm, no." 

"What? Yes they were, I bought them." 

"I was answering your first question. Cherry-flavoured will not suffice." 

John pinched the bridge of his nose. "You're serious?" 

"Deathly. Our only option here is to forgo the condom." 

"No, Sherlock," he protested, though he had to admit his resolve was weakening. 

"Why not? I'm not asking you to engage in full-on intercourse!" 

"Sherlock, when you've studied sexually transmitted diseases and actually dealt with patients suffering from chlamydia, gonorrhea, syphilis, and herpes, you really start to see the merits in safe-sex practices. So," he clapped his hands together. "If you're dead-set against cherry flavoured condoms—" 

"I am," Sherlock confirmed. 

"—then do you have any requests for other condoms?" 

"Glow-in-the-dark." 

"I'm serious, Sherlock." 

"So am I. What if the power goes out while we're," he paused to locate a suitable term, " _experimenting._ I'll need to be able to locate your genitals as efficiently as—" 

"Oh my god. No glow-in-the-dark. And I'll make a mental note not to buy more cherry-flavoured ones. Are there any other types you'd prefer?" 

"Just get regular ones," he muttered. 

"Of course I'm the one who has to go out and buy them," John sighed. "Alright. I'll be off then." He headed for the door. 

"John?" Sherlock called after him. His voice sounded smaller. There was something distinctly vulnerable about his tone. John's steps slowed, his scowl smoothed away. 

"Yes?" 

Sherlock's gaze was unfocused. He worried his lips absently. "Do try and hurry. I'd like to complete the experiment relatively soon." 

John flipped him off, before slipping into his shoes and descending the stairs. He tried to slink out the building as quietly as possible. He really wasn't in the mood to be accosted by Mrs. Hudson. She'd probably be delighted if she knew what they were up to, and that was precisely why he didn't want her to know. 

While waiting for a taxi, John hazarded a glance back at the window, catching sight of the curtain being hurriedly yanked. He smirked. No doubt Sherlock was watching him leave but didn't want to be caught. John debated taking his time purchasing the condoms. He could stop for a bite to eat first, or order some takeout. It would probably drive Sherlock up the wall if he had to wait long. The only downside was that John would have to wait, too. No, he decided. Better to just grab a box of condoms and hurry back to Baker Street.

The nearest convenience store was about ten minutes away, but of course the only condoms they had in stock were either XS or XL. He didn't think his pride could survive the former, and Sherlock would never let him hear the end of it if he came back to the flat with an XL box. It took John an additional fifteen minutes to get to a different store and make his purchase there. By the time he returned to 221B Baker Street, John had had ample time to consider the ramifications of what he and Sherlock were about to do. 

Sure, it was only a blowjob, but for all he knew, it could completely alter their dynamic. What if Sherlock was able to deduce from John's reactions that he was not only attracted to him physically, but also harboured romantic feelings? Things could get awkward fairly quickly. 

Sherlock had made it no secret how he despised the notion of romantic entanglement. John's feelings towards him would surely be unwelcome. It would complicate their relationship and create tension between them. Why had he ever thought agreeing to this was a good idea? 

John's hand tightened around the box of condoms. He paid the taxi driver hurriedly, but his steps towards the flat were slow and reluctant. He felt like a soldier marching off into battle. His heart hammered against his ribs, and every muscle in his body was taut with dread. 

"Took you long enough," Sherlock's petulant tone reverberated through the flat. 

John shut the door behind himself silently, before divesting himself of his coat and shoes. Sherlock was sprawled dramatically across the sofa. 

"Here it comes," Sherlock muttered at the same time John said, "we need to talk." 

There was a pause as the two silently assessed the other. 

"Here what comes?" John demanded. 

"You're so predictable," Sherlock sighed. "Leave you alone long enough and you start overthinking." 

"Me? I'm the one who overthinks." 

Sherlock sat up. "You have to admit you're a bit theatrical." 

" _I'm_ theatrical?"

"Yes, do try to keep up." Sherlock's gaze raked down the length of John's body with a heat and intensity that couldn't have made him feel more exposed if he was actually naked. "Ah, you remembered the condoms."

"Yes, of course I remembered. That's the whole reason I left."

"I was hoping you'd forget about them," Sherlock admitted. "They are unnecessary, after all." 

"Yeah, well, next time you get tested bring me along and we can avoid all this." Sherlock perked up at those words, and John consequently tensed. What the hell was he saying? Next time? That seemed awfully presumptuous, and he didn't want to give Sherlock the wrong impression. "Er, I only meant--" 

"I know what you meant. I'm not an idiot," Sherlock snapped, but he didn't look irritated. If his fidgeting was suggestive of anything, he almost seemed nervous. "If you're still willing, might we proceed?" 

John's tongue felt clumsy and thick. He should tell him that he's changed his mind. Any sane person in his situation would decline, but then, he'd never been very good at telling Sherlock "no." 

"Um," he licked his lips nervously. "Yeah, alright." 

"It's just a blowjob," Sherlock chided. "You needn't be so tense." 

"Oh, needn't I?" 

"You get so snippy when you're nervous." 

"I am not nervous!" John protested, and he wasn't. Sherlock's obnoxious personality had a way of overriding his nervousness with irritation. He wasn't sure which was preferable in this instance. 

"Of course not." 

He could hear the smirk in Sherlock's voice. "Shut up." 

"Gladly." 

Sherlock dropped to his knees for the second time that night. He made quick work of John's zipper, tugging his trousers down without a modicum of embarrassment or hesitation. 

John removed a condom from the foil packet, and held it awkwardly. He couldn't help fidgeting, and of course Sherlock noticed. 

"If you need something to do, you could help by taking off your shirt." 

John's first instinct was to retort or flip him off, but instead he bit his tongue and hastily complied. He let his shirt drop to the floor in a pool of crinkled fabric. Sherlock's eyes immediately snapped upwards, roving shamelessly over his bare-chest. John fought the urge to cover himself like a blushing virgin. He may not have the greatest physique, and he indulged in beer more often than he should, but he figured he was decent-looking. 

His state of partial undress seemed to render Sherlock speechless, though he couldn't determine why. Goosebumps lifted along his bare arms, and he battled the impulse to cross his arms over his chest. He'd feel a lot less uncomfortable if he wasn't the only one shirtless. 

"You're still dressed," he noted aloud. 

"Yes," Sherlock agreed, his eyes unblinking, as if in a trance. 

"You're not taking your clothes off?" 

"Why would I?" 

"Oh. No reason." John can't think up a good argument, even though he'd really like to see Sherlock sans clothes. "Are you planning on continuing anytime soon? Not to sound pushy, but there's a bit of a draught." He wasn't lying. His nipples were hardening from the cool air, and he couldn't repress a shiver. 

Wordlessly, Sherlock continued his task of undressing John. By the time he was fully naked, John's heart had relocated to his throat. 

He was already getting hard from this alone. Sherlock hadn't even touched him yet. He wasn't sure he'd be able to make it through this encounter without dying of mortification. 

A few seconds passed, Sherlock making no attempt to touch him. 

"Please tell me you're not mentally measuring my anatomy." 

"Hm?" The sound of John's voice seemed to break Sherlock out of whatever daze he'd been in. "No, I was just... analyzing it." 

"Of course you were," he shook his head. It was difficult to feign exasperation. He definitely wasn't losing any hardness. "Care to share your thoughts with the class? Am I woefully below average?"

"What? No, don't be stupid you're, er, it's," he lowered his voice. "Nice." 

"Nice?" John echoed. He felt almost delirious. "You think my cock is nice. Sherlock Holmes thinks I have a nice cock!" he crowed, hysteria edging into his declaration. 

"Put that on a t-shirt, why don't you," he snapped. 

"You know, I think I will."

"Why does it come as a surprise to you that I find you aesthetically pleasing? You're not bad-looking."

 _Not bad-looking, he says._ Coming from Sherlock, that was about the equivalent of receiving a ten page love letter. "You don't need to make me feel better," John assured him with a laugh. "I'm fully aware of how plain and boring I look." 

"You're not boring!" Sherlock looked affronted. His hands flexed and tightened around John's thighs, but he didn't seem conscious of the movement. "If you were I would never have agreed to share a flat with you." 

"Right, my bad." John couldn't hold back a smile. Sherlock was conceited, churlish and a total arse, but he was occasionally very sweet. John had to fight the sudden impulse to yank Sherlock back to his regular height and snog him senseless. He didn't, of course, because he wasn't sure his actions would be appreciated. There was also the possibility it would compromise Sherlock's highly important experiment. 

"Yes," Sherlock agreed belatedly. "It was your bad. Don't say stupid things like that again." 

His heart did an odd flutter in his chest. This entire experience was not good for his health. If anything, it was going to make getting over Sherlock even more difficult. 

Sherlock's throat rumbled like the low drone of thunder. “Back to the experiment."

He held his hand out, and it took John a moment to realize he was supposed to hand over the condom. Sherlock worked it over his cock methodically. His expression was blank, and seemingly unaffected, his touch almost clinical. It shouldn't have been at all arousing, but some how it was. 

"Is it better to wait until you're fully erect, or to use suction as a method for arousing you?” 

Heat flooded John’s face. He couldn't believe they were actually having this discussion. “Nope, no. I can't do this. I thought I could, but there are just some boundaries one shouldn't cross with their flatma—” His voice broke off into a gasp as Sherlock leaned forwards to press his perfectly shaped lips to the head of John’s cock. With his eyes closed and his lips slightly parted, his expression could only be described as rapturous. All the blood in John's body rushed southwards. He was absurdly hard from the mere sight of Sherlock's lips glancing his cock. He hadn't even done anything, and John was already trying to calm himself. He inhaled heavily, holding his breath for a couple seconds, before slowly releasing it. _Calm down_ he pleaded with himself. He wasn't a bloody teenager anymore, and he'd be damned if Sherlock ended up writing some scientific paper about how he came within thirty-seconds. 

His train of thought fractured when Sherlock started to suck. A squeak escaped John before he could suppress it. Not the manliest or sexiest of sounds, but in his defense he was currently being sucked off by the most gorgeous man he'd ever laid eyes on. Possibly the most gorgeous man to exist, in the history of anyone ever. 

Sherlock's tongue traced along the underside of his shaft, before swirling around the head. 

"I-it's not a bloody lollipop," he informed. When did his voice get so strained? 

Sherlock pulled off him with a wet pop. He licked his lips shamelessly. "Oh, I know. This is _better_." 

Before John could formulate any sort of riposte or quip, Sherlock lips were closing around him once more, sucking him into the warmth of his mouth. John squirmed, his hips straining to thrust into the wet heat presented to him. The idea of grabbing onto Sherlock's curls and fucking his mouth was entirely too tempting, but he had the decency to restrain himself. 

Sherlock eased John's shaft further inside his mouth. John's thighs shook, and it took all his strength to remain standing. He repeated a mantra of _calm down, relax_ , but when Sherlock swallowed around him, he had no hope of remaining composed. 

"Shit!" He threw his head back. Sherlock's lips twitched into a faint smirk as he continued to deep-throat him. His hips bucked forwards without his consent, but Sherlock was well prepared. "Where did you learn to do that?" 

Sherlock swallowed around him once more, before drawing back for air. His reddened, bowed lips were swollen. John wanted to kiss them. He wanted to kiss him so bad that the need manifested as a physical ache. Before Sherlock could continue what he'd set out to do, John dropped to his knees as well. 

Sherlock's brows knitted together, but before he could voice the questions surely running through his brain, John leaned it. He meant it to be only a quick glide of lips, but he found he couldn't tear himself away once he'd started. He sucked on Sherlock's lower lip fervently, reveling in the high gasp Sherlock released. He seized Sherlock's momentary lapse in control to slip his tongue inside the other man's mouth. He charted out the inside of his mouth, dragging slowly along the roof of it. Their tongues met, and the intimacy of it sent a shiver down his spine. 

He was kissing Sherlock Holmes! Him! John Watson was kissing the man he'd admired and lusted after for years. Inhaling sharply through his nose, John pulled back slightly in order to trap Sherlock's lower lip between his teeth. He nibbled teasingly, making sure to only apply light pressure. 

Sherlock had seemed so confident with a cock in his mouth, but kissing didn't seem to be his area of expertise. His responses were tentative and shy. John wanted to completely ravage the other man's mouth.

He probably could've continued kissing Sherlock all night, but his cock throbbed, demanding his undivided attention. John broke the kiss, pulling back in order to assess Sherlock while they both worked to catch their breath. 

Sherlock's pale eyes were almost entirely eclipsed by pupil, and a flush sat high on his cheeks. His hair was mussed, his lips swollen, and he looked completely disheveled. 

"My... my mouth tastes like rubber," Sherlock husked out. 

A laugh bubbled past John's lips. "Would taste like cherry if you'd just accepted flavoured condoms." 

"Shut up." 

"Or what?" 

"Or I'll leave you to take care of yourself." 

"Would you really?" he wondered. From the bulge in Sherlock's trousers, he thought it fair to say that they were both enjoying themselves. 

"Why don't you try me and see?" 

"I'd rather not risk it," John admitted with a grin. 

Sherlock's eyes widened as if caught off-guard, before he averted his gaze. "Well?" he muttered. 

"What?" 

"How am I supposed to suck you off if you're kneeling?" 

"Oh." John scrambled back to his feet. "Right." 

Sherlock didn't need any prompting to resume his earlier ministrations. He guided John's cock to his mouth with his fist, before closing his lips around the head. His lashes fluttered against his cheeks as he sucked John deeper into his mouth. 

John couldn't hold back a low groan. He should have known Sherlock would give head like a pro. He was absurdly good at just about _everything._

"Shit. _Shit!_ " He was trembling, that's how good it was. "How are you so good at this?"

Sherlock didn't bother stopping to answer. Instead, he continued the rhythm he'd set, bobbing his head in time to the thrusts that John had no control over. Sherlock hummed contentedly around him, and John felt as if the air had been knocked out of him. 

"S-so good," he babbled. "So good. _Sherlock!_ " 

Sherlock pulled off him, gasping in breath like it was a commodity. "John." 

He grunted in response. 

"Put your hands in my hair." 

He had no issue with that order. He twined his fingers in Sherlock's beautiful dark curls, tugging at the strands experimentally. He half-expected Sherlock to glare at him, but instead the man let out a soft moan. _Shit._ Did Sherlock Holmes have a hair-pulling kink?

John tightened his hold on Sherlock's hair, guiding the man back towards his throbbing arousal. Sherlock's lips yielded to the press of his cock, and he suckled him eagerly. John's hips bucked into Sherlock's mouth. He only lasted a few more thrusts before his vision went stark and white. His knees buckled under him, and really, it was a marvel he'd been able to remain on his feet as long as he had.

He covered his face with his hands, but Sherlock immediately batted them away. 

"Let me see you," Sherlock rumbled. If John hadn't already come, Sherlock's smooth baritone would have done it for him. 

John shivered through the aftershocks. "F-fuck. Sherlock. That was amazing. You're amazing." 

Sherlock groaned, and John eyes snapped open. "Let me take care of you," he blurted.

Sherlock shook his head. "Already been taken care of." 

John glanced down. Sherlock wasn't lying. There was a large wet spot on his trousers, but it was obvious he'd already come. John felt disappointed, and oddly cheated that he hadn't gotten to watch Sherlock's face while his pleasure peaked. He wasn't too terribly disappointed, of course. He'd just had one of the best orgasms of his life, and gotten to kiss Sherlock. Hoping for anything more just seemed greedy. 

"So," he cleared his throat. "Did you collect enough data for your experiment?" 

"It was more than sufficient." 

John reached for his shirt, tugging it on lazily. "Are you ever gonna tell me what it was for?" 

Sherlock didn't meet his eyes. "It was a formal experiment that relied on the scientific method. It needed to be tested. And now it has been." 

John fought the urge to roll his eyes. Only Sherlock could be so cryptic. "Let me guess, your hypothesis was that I'd blow my load within five seconds." 

"The hypothesis had little to do with your responses." 

"Oh?" He pressed, but Sherlock remained stubbornly silent. He was clearly missing something. Sherlock's shoulders were hiked up almost to his ears, and his stance was tense and defensive. "Hey," John lifted Sherlock's chin upwards, forcing him to meet his gaze. "If something's wrong, talk to me."

Sherlock took a deep, restorative breath. "I wanted to know for certain if I was really attracted to you, and if any hypothetical attraction could be satisfied by a sexual encounter. I was hoping, at least on a subconscious level, that this would be enough for me to 'get you out of my system,' as it were."

Oh. _Oh._ John wet his lips with his tongue. His insides were probably going to be bruised from how hard his heart was beating. "And did it work?" 

"No." 

"That's..." John's lips slipped into a grin that he couldn't repress even if he wanted to. "Good."

Sherlock whipped his head sharply. "Is it?" 

John scooted closer, wrapping a hand around Sherlock's waist. "Oh, yes. Because I don't plan on letting you go anytime soon, Mr. Holmes."

Sherlock's lips slackened. "I never anticipated..." 

"What?" John pressed. 

"You're not supposed to like me. People don't like me." His eyes were wide. "People tolerate me, but even asking for that much is..." 

"Sherlock," John said quietly. "I like you more than I've ever liked anyone." He didn't say, _I love you_ , because he wasn't sure he was ready to say it, and he doubted Sherlock was ready to hear it, either. "If I didn't like you," he added, "I wouldn't have agreed to this."

Sherlock's eyes darted rapidly over his face. He inched closer, grabbing John's wrist. "Say that again." 

"I like you. I like you so much." 

An almost childlike wonder crept over Sherlock's face. "Your pulse was steady. You weren't lying." 

"I would never lie to you." He reconsidered his words. "Not about something like this, anyway." 

Sherlock all but collapsed against him, burrowing so that they were pressed firmly against each other. Their bodies fit so very perfect together. "In that case, I have several other experiments we could test."

John laughed. "If they're anything like this one, I'm looking forward to it." 

"I do have one condition, though." 

"Oh?" he brushed a lock of hair out of Sherlock's face. Now that he knew he was allowed to touch him, he didn't have any interest in stopping.

Sherlock's expression darkened. "Get rid of those ridiculous cherry-flavoured condoms."

"Hey, I paid good money for them!" 

"Their mere presence in this flat is an insult. Throw them away." 

"Fine," John agreed, because sometimes life was about compromise, and he would do just about anything for Sherlock. 

"I'm glad you're being reasonable." Sherlock extricated himself from John's arms. "Now, I have a list of other sexual experiments we can engage in. The list is in my bedroom if you'd like to peruse it." 

"What? Now?" 

Sherlock huffed. "Yes, of course now." 

"Alright," John acquiesced. He supposed performing one or two more experiments that night couldn't hurt.

**Author's Note:**

> my sherlock sideblog is over at [vintage--lilacs](https://vintage--lilacs.tumblr.com/)
> 
> thanks for reading!


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